Drawer slide with synchronization of the slide rail runs are made known, for example, by DE-40 19 124 C2, DE-42 26 812 A1 and DE-92 19 064 U1, that refer back to the same applicant.
DE-42 26 812 A1 and DE-92 19 064 U1, which refers back to it, make known a drawer slide with full extension and a traction mechanism, which consists of a drawer rail, a center rail and a cabinet rail, so that a load transferring carriage is located between the rails. In order to achieve a synchronous shift between the center rail when the drawer rails slide, a traction mechanism (rope, chain, etc.) is provided, which runs over the deflection rollers on the center rail. The upper trunk of the traction mechanism is connected to both ends of the upper carriage, while the lower trunk is connected to the ends of the lower carriage.
DE-40 19 124 C2 describes a full extension that corresponds to the type of differential slide with a drawer that has a cabinet rail with cabinet rail rollers, a center rail and a drawer rail; whereby, the center roller has deflection rollers, across which a traction band is guided, which is fastened to the cabinet rail so that when the drawer rail moves, the center rail goes along synchronously. In order to achieve a slide that is clearance-free and play-free and has a synchronous glide, it is provided that the carriage is located movable on the center rail so that the drawer rail engages clearance-free and play-free with the carriage and the deflection rollers, and that the traction band has a carrier, which moves the carriage in given positions and further forms a catch on the traction band that engages in a recess of the drawer rail and has the means on which the drawer, during its closing, sinks automatically.
Synchronization systems of this type generally have the purpose of adjusting deviations of relative movements of the slide rails, especially the cabinet-, center- and drawer rails of full extension systems, which are systematically present after each opening and closing.
The deviations of relative movements of the slide rails are recognizable by a depth gap (distance of the drawer front's inner surface to the cabinet's front face surface) of the drawer, that increases, for example, from approximately 1–1.5 mm to 3–4 mm if the drawer is pulled up and subsequently pushed in again. The front gap also increases constantly, so that this error, without a suitable compensation device, can only be corrected if the user presses the drawer with increased force against the rear stop. The reasons for the depth gap errors are many-fold and lead back to the slipperiness and elasticity of the rollers, the buckling and/or bending of the rail sheet metal and tilting of the slides and wheels during the drawer's openings and closings.
The disadvantage of compensation mechanisms of the slide rail's synchronous running errors, according to the state of the art specified above, is that for the reasons described above, despite the synchronization, synchronous running errors still occur and the devices made are relatively complicated and, therefore, are cost-intensive and susceptible to needing maintenance and repairs.